Exclusive Features

Sky Glow: Closing the Gap Between Differing Views, Part II

Sky Glow: Closing the Gap Between Differing Views, Part II

Growing Municipal Concern  

So far, he’s been lucky, says Paul Verheyen, Director of Public Works for the City of Webster Groves, Missouri. He’s been able to resolve citizen complaints about light trespass on a one-by-one basis. Take the man who complained that light from a nearby street lamp was shining into his bedroom.

“So I talked with some other cities and the supplier and we put some reflective aluminum on the backside of the fixture so that it pushes all the light toward the street,” says Verheyen. In another example, after a public utility swap from high-pressure sodium to LED left one resident’s backyard bathed in light, Verheyen persuaded the utility to reduce the light level from that one fixture. “We haven’t gotten a call back.”

Oh, that it were this easy! The controversy over light pollution in urban environments continues to bloom, along with the reported rise of global light pollution. A report released in November shows an increase of approximately two percent per year according to the German researchers at the GFZ German Research Centre for Geosciences who analyzed five years of satellite images from 2012 to 2016. The results from that study were widely disseminated by the media, providing fresh data for public debate around how light at night is hazardous to everything from migrating birds to human sleep cycles.

In Lawrence, Kansas, a citizen group, called the Lawrence Alliance for Responsible Lighting, is pushing for the city to switch gears in the middle of a $4.4 million LED installation and substitute 3000k LEDs for the 4000k previously specified. According to the Lawrence Journal-World, the ad hoc group is also asking for better direction and shielding on the lights. As of this writing, no final decision has been made. Lawrence exemplifies the conflict that arises between those who cite the need for pubic safety and those who come down on the side of nature.

City Engineers Caught in the Middle  

In the meantime, most municipalities and public entities are trying to bridge that gap. Problem is, there are differing, and oftentimes contradictory, guidelines.

“The Illuminating Engineering Society (IES) used cutoff classifications for almost two decades, which help measure how much light goes up into the sky,” says Shaun Fillion, LC Educator IALD who serves as RAB’s Lighting Studio Manager. “The cutoff classification system was incorporated into the ordinances for many cities across the US. Then in 2011, the Model Lighting Ordinance (MLO) was created in a collaboration with IES and the International Dark Sky Association (IDA), including a Luminaire Classification System (LCS) with the BUG ratings which was meant to supersede cutoff classifications. The BUG ratings are really useful when a lighting designer is trying to decide which fixture to use, because it not only tells you how much lighting is going up, but how much is going in the direction you want and how much is going back. That’s helpful if you’ve got a sidewalk that you’re trying to light.”

Even though BUG ratings allow lighting designers to quantify backlight, uplight and glare, many municipalities still rely on the cutoff classifications, and have not yet adopted the current LCS system. “Unless it’s a decorative luminaire, most outdoor lighting is being designed for full cutoff or uplight rating of zero in order to comply with municipal requirements,“ adds Fillion.

“There’s a tension there because what’s happening is, most municipalities and commercial interests want to create lighting that’s going to keep them out of a courthouse being sued for slip and fall,” adds Jane Slade MID, LC, DLF, IES and Specification Sales Manager for RAB.

While municipal civil servants strive for appropriate lighting levels for public safety, often drafting ordinances based on outdated data, at the same time, they’re trying to be sensitive to environmental concerns. “For example, I’m working with a municipality and they’re insisting on us putting shields on a fixture that is already directing light with the optics of the fixture. I applaud them for wanting to shield light across the property line, but at the same time it’s likely going to be a superfluous addition to the fixture and they really didn’t understand that.”

Fillion adds, “We’re giving mixed messages to municipalities as an industry right now. We’re saying ‘minimize your lighting because of the environment’ and we’re saying ‘provide lots of light for security.’ I think – and I don’t see this on the horizon yet, but – developing a unified document that addresses both issues from our industry and letting that reach municipalities will help to resolve these ordinances that include impossibilities, with contrary foot candle requirements on the same site.”

Reaching Critical Mass  

If there is one consensus in the midst of many points of view regarding light pollution it’s this: it has the potential to be greatly reduced through technology, design innovation, informed application and widespread education. Many assert this should emanate from the lighting industry.

“Let’s bring it up to the highest level of our profession,” says Fillion, who is also Program Director for the MPS-L Lighting Design program at the New York School of Interior Design. “Let’s let the people who are writing the standards hash it out in the technical committee of the IES.”

Exactly what would be hashed out is some kind of middle ground, which would take into account the need for public safety, technical advances in lighting optics, improved security cameras that function well in low light, and sophisticated controls that trigger light only when and where it is needed. Simply put, the regulations need to keep up with the technology.

“I definitely want to help bring consensus to the industry, continue the conversation so that we start to realize that we’re not really talking about the same set of guidelines when we talk about lighting for safety and lighting for the environment,” says Slade, who is also an adjunct professor at Mount Ida College in Newton, Massachusetts.

If one concedes that light pollution is indeed a concern, one could also hope that media coverage of both sides of the debate, e.g. public safety versus a healthy planet, will eventually trickle down to the individual consumer, who might shopping for lighting at their local hardware store or from their laptop. Like any public awareness campaign, from wearing seat belts to recycling, it takes a steady drumbeat of awareness.

While work continues to bridge this gap, here are few reminders on how municipalities can cut down on light pollution:

  1. Avoid shining light upward.
  2. Do photometric studies whenever possible so that you’re not over-illuminating, and you really understand the statistics of foot candles that you’re creating.
  3. Lower CCTs when possible.
  4. Controls should factor in your decision – the idea of incorporating lighting controls as a requirement to help minimize any light pollution.
  5. Hire a lighting designer.


Shaun Fillion and Jane Slade will be giving a talk at the LEDucation conference presented by the Designers Lighting Forum of New York on March 13th in New York City. The name of their talk is: Stargazing vs. Safety: The dilemma of exterior lighting. For more information on the event, click here.

Tagged with , ,
Jean Whatley

Comment on the story

Your email address will not be published. Required fields are marked *